Osmium Staining Fails to Detect Early Cell Wall Damage in Brown Rot Wood Decay

IAWA Journal ◽  
1994 ◽  
Vol 15 (2) ◽  
pp. 133-136
Author(s):  
W. Wayne Wilcox
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Walls ◽  
Osmium Tetroxide ◽  
Wood Decay ◽  
Brown Rot ◽  
X Ray ◽  
Polarised Light ◽  
Early Manifestation ◽  
Scanning Electron

Loss of cell wall birefringence under polarised light in the light microscope is an important diagnostic characteristic for early stages of brown rot wood decay not available with the scanning electron microscope (SEM). Osmium tetroxide staining was explored as a means of visualising this early manifestation of decay in the SEM, but proved unsuccessful as X-ray spectroscopy indicated that osmium was evenly distributed across both distorted and non-distorted cell walls.

Comparison of Scanning Electron Microscopy and Light Microscopy for the Diagnosis of Early Stages of Brown Rot Wood Decay

IAWA Journal ◽  
1993 ◽  
Vol 14 (3) ◽  
pp. 219-226 ◽  
Author(s):  
W. Wayne Wilcox
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Cell Walls ◽  
Wood Decay ◽  
Brown Rot ◽  
Early Stages ◽  
Polarised Light ◽  
Scanning Electron

As part of a larger study of the microscopical characteristics useful in diagnosing early stages of decay, an opportunity was created to compare the ability of light microscopy (LM) and scanning electron microscopy (SEM) to image these features. Although most features could be imaged by both technologies, imaging was much easier in the SEM because it was being used at the low end of its resolution and magnification capability while the LM was near the high end of its limitations. One important feature which could not be imaged in SEM was the earliest attack on the cell walls, a feature which was visible under polarised light in the LM.

Wood Petrifaction: and aspect of biomineralogy

1979 ◽  
Vol 27 (4) ◽  
pp. 377 ◽  
Author(s):  
G Scurfield
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
X Ray Diffraction ◽  
Intercellular Substance ◽  
X Ray ◽  
Colloidal Form ◽  
Cell Lumina ◽  
Mineral Deposition ◽  
Wall Components ◽  
Scanning Electron

Light microscopy, scanning electron microscopy, X-ray diffraction and differential thermal analysis have been used to examine the structure and mineralogical make-up of 79 Australian petrified woods. Initiation of petrifaction appears to rely on the provision of a substrate with inherent porosity, with the substrate components chemically rather inert and only slowly degraded at normal temperatures and pressures under conditions probably most often acid and tending to anaerobic, and the pores sufficiently large to allow access of an appropriate mineral in ionic or colloidal form in water. Stages in the process include entry of mineral solution into the wood via splits or checks, cell lumina, and other voids; permeation of cell walls; progressive dissolution of cell wall components beginning largely with lignin and accompanied by a build-up of a mineral framework adequate for maintaining the dimensional stability of the wood; mineral deposition in cell lumina after cell wall replacement as a continuous, intermittent, perhaps separate, but not obligatory event; mineral deposition in voids present or formed by dissolution of intercellular substance as a separate, but not obligatory event; and final lithification involving loss of water and perhaps replacement of one mineral by another.

Ultrastructure of conidiogenesis and appendage ontogeny in the coelomycete Bartalinia robillardoides

2003 ◽  
Vol 81 (11) ◽  
pp. 1083-1090 ◽  
Author(s):  
M KM Wong ◽  
E BG Jones ◽  
M A Abdel-Wahab ◽  
D WT Au ◽  
L LP Vrijmoed
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Walls ◽  
Apical Cell ◽  
Conidiogenous Cell ◽  
Dense Layer ◽  
Basal Cells ◽  
Outer Electron ◽  
Transmission Electron ◽  
Scanning Electron

Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi was studied at the light microscope, scanning electron microscope, and transmission electron microscope levels. Conidiogenesis in B. robillardoides is holoblastic. Appendage ontogeny begins as a cellular outgrowth of the apical and the basal cells of the young conidium, the former developing prior to the basal appendage. Conidia detach from the conidiogenous cells schizolytically. Mature conidial cell walls comprise two layers: an outer electron-dense layer, 30–38 nm, and an inner less electron-dense layer, 100–125 nm. The apical appendages arise from an outgrowth of the apical cell, which then branches to form the appendages. The single basal appendage arises from the junction between the basal cell of the conidium and the conidiogenous cell prior to conidial detachment from the conidiogenous cell, as an outgrowth of the conidial cell wall. Conidial appendage ontogeny is compared with those of other coelomycetes.Key words: Annellidic, appendage ontogeny, coelomycetes, holoblastic.

Some Ultrastructural Aspects of Vensus’s-Flytrap

1967 ◽  
Vol 25 ◽  
pp. 72-73
Author(s):  
Daniel W. Schwab ◽  
James Scala ◽  
Evelyn B. Simmons
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Surface Area ◽  
Digestive Gland ◽  
Cell Walls ◽  
Osmium Tetroxide ◽  
Gland Cells ◽  
Dionaea Muscipula ◽  
Usual Manner ◽  
Tubular Inclusions

Recently a study was begun in this laboratory on the insectivorous Venus's-flytrap (Dionaea muscipula Ellis) at all levels of microscopy, with emphasis on ultrastructure. Two features, among others, that stand out in the electron microscope after glutaraldehyde-osmium tetroxide fixation are: (1) a highly-convoluted plasmalemma in the digestive gland cells and (2) a tubular network in the cell walls of the trap lobe.The cell walls and plasmalemma of the digestive gland appear to be highly specialized, in that numerous microvilli-like outgrowths on the walls cause a myriad of invaginations in the plasmalemma (Fig. 1). Thus the plasmalemma has a tremendous surface area which would facilitate its functioning as a secretory and absorptive membrane. Also of interest in the digestive gland are the two distinctly different cell wall inclusions seen in Fig. 2. The bundle of tubular inclusions (Fig. 2, lower half) are apparently specialized plasmodesmata which do not traverse cell walls in the usual manner but run laterally around the cell.

Etudes du cours des hyphes de Fomes fomentarius dans le bois d'Aesculus hippocastanum au microscope électronique à balayage

1976 ◽  
Vol 54 (19) ◽  
pp. 2231-2238 ◽  
Author(s):  
Stefan Plank ◽  
Franz Wolkinger
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Cell Walls ◽  
Representative Specimen ◽  
Primary Role ◽  
Fomes Fomentarius ◽  
Sem Study ◽  
Secreted Enzymes ◽  
Scanning Electron

In a scanning electron microscope (SEM) study, the passage of penetrating hyphae of Fomes fomentarius (L.ex Fr.)Kickx was observed in a representative specimen of Aesculus hippocastanum L. The fungus hyphae appear in all cells of the wood and break through in numerous areas of the cell walls. It was noted that many pits serving as passageways were found; however, the cell wall was observed to be penetrated in many areas devoid of such pits. Apically secreted enzymes probably played a primary role in the process. The primary bore passages are widened by means of lateral enzyme secretion. The depth and sharpness of the SEM photographs are remarkable in that they allow one to follow the passage of the hyphae quite well.

Fabrication of Neodymium-Based Superconducting Bulk Materials

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2670-2675 ◽  
Author(s):  
A. VECCHIONE ◽  
M. GOMBOS ◽  
P. TEDESCO ◽  
S. PACE
Keyword(s):  
Electron Microscope ◽  
Growth Dynamics ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Polarised Light ◽  
Particles Size Distribution ◽  
Temperature Window ◽  
Scanning Electron

We report on Nd123 bulk samples directionally solidified in air prepared with Ba-rich Nd422 doping brown phase by top seeding growth (TSG). By using this technique, we have fabricated single domain pellets up to 3.5 cm of diameter and 1 cm of thickness. The crystallographic alignment and the texture of samples have been investigated by means of polarised light optical microscopy, scanning electron microscope, supplemented by energy dispersive spectroscopy and X-ray diffraction analysis. The resulting microstructures have shown Nd 1 Ba 2 Cu 3 O 6+d domains, and Nd 4 Ba 2 Cu 2 O 10-d particles' size distribution, depending on the used values of the fabrication process's parameters. In particular, we investigated the influence both of the growth temperature window and of the cooling rate on the growth dynamics of the samples and on the precipitates segregation mechanism was analysed.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

Observations of thick and thin sections in a field-emission SEM

1994 ◽  
Vol 52 ◽  
pp. 1018-1019
Author(s):  
W. P. Wergin ◽  
S. Roy ◽  
E. F. Erbe ◽  
C. A. Murphy ◽  
C. D. Pooley
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.

PENGGUNAAN TiO2 PARTIKEL NANO HASIL SINTESIS BERBASIS AIR MENGGUNAKAN METODA SOL-GEL PADA BAHAN KAPAS SEBAGAI APLIKASI UNTUK TEKSTIL ANTI UV

Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sol Gel ◽  
Crosslinking Agent ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
X Ray ◽  
Infra Red ◽  
Scanning Electron

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.

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